Synchronism-indicator.



No. 848,970. PATENTED APR. 2, 1907 P. L. CLARKr SYNGHRONISM INDICATOR.

APPLICATION FILED O0T.19, 1903.

PL Q. 1

WLCncSscs: Inventor:

. I Paul lV.CIcLrk UNITED STATE ATENT OFFIOE.

PAUL L. CLARK, OF CHICAGO, ILLINOIS, ASSIGNOR TO ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

SYNCHRONESWI-INDICATOR.

ri s pecification of Letters Patent.

Patented April 2., 19.6

Application fil d October 193903.. seraiia. 177,587.

To all], whom it may concern:

Be it known that 1, PAUL L. CLARK, a citizen of the United States, residing in Chicago, in the county of Cook, in the State of Illinois,

have invented certain new and useful Im-v provements in Synchronism-Indicators, of which the following is a specification.

This invention relates to alternating-cunother machines already running and with which it is to be connected in multiple. v

It is well known that in order to safely cou- 'ple two or more such machines in parallel they must substantially coincide in speed and phase. Ordinarily one or more incandescent signal-lamps are connected in circuit with the machines to be coupled and in shunt to the switch, either across corresponding leads if the method of synchronizingis dark or across dissimilar leads if the bright method is to be used. proaches synchronism the fluctuations of the signal-lamps be'come slower and slower until the operator guesses that the machines are nearly in ste He then throws the switch and trusts to uck tohit the instant when the current-waves most nearly coincide.

My invention aims to provide a device whi h will indicate very closely the instant when the switch should be closed, thus eliminating all guesswork and the troubles which result from mistakes in. judgment on the part of the operator. The invention consists in a small constant-current transformer comprising two relatively movable coils, one of which is operatively connected with an indicator, such as a signal-lamp, the other coil being connected across the controlling switch. When the machines are not in step, the cur- .rent in the latter coil repels the other coil and causes them to separate against the tension of a spring. The secondary current induced in the repelled coil at the same time lights up the signal-lamp. As the machines approach in step andthe difference in potential de. creases the repulsive effect of the primary coil decreases and the secondary coil is moved back by the spring toward a position coincident with the primary until it abuts against a stop. Any further decrease in pothe machines. As the machine aptential due to the machines coming still closer into step will cause the lamp to darken, and when it goes out the switch may be safely thrown. In other words, the lamp lights up as the exchange of current begins to take place between the machines and attains its maximum brilliancy when the current in the secondary reaches, say, one-half an ampere, (the current for a sixteen-c andle-power lamp.) Any further rise in voltage in the primary, due to the machine's getting further out of phase, will operate to repel the bal anced secondary, whose movement toward a more distant position result-s in-keeping thesecondary current at one-half an ampere,

The repulsive effect increases through half' the period of phase displacement and decreases through the half when the machines are coming back into step. The lamp therefore maintains an even brilliancy until the potential has fallen nearly to zero, and the light diminishes only during the period when there is little exchange of current between the exact instant when the switch may be safely closed;

I11 the accompanying drawings, Figure 1 is a diagranr of circuits showing my invention. Fig. 2 is a cross-section of the indicating device on a large scale. Fig. 3 is a frontelevation, and Fig. 4 is a modification.

' The machine lis connected with the mains 2 3' -:L by the controlling-switch 5 and is sup posed to be running at full speed. The machine 6 is coming up to speed, its controllingswitch 7 being open. The primary coil 8 of my indicating device is connected across the switch to similar leads of the circuit. The secondary coil 9 is movable, being preferably pivoted on a transverse shaft 10, journaled in bearings 10", and is maintained yieldingly against a stop 11, preferablv by a spring,

which may be coiled on the shaft 10 as at 12 It is thus easy to determine IOC , 1 7,- completes t .The operation ondary coil approaches aposition at right an- ;gles with the primaryfso that the current in the secondary is maintainedconstant'.

, The stop 11 is so located hat he-'sec'ondary cannot become exactly parallel'with the primary, so that the repulsive eflrmt isalwa. s

1n the same direction. This stop, and tie bearings 10 are-carried on any suitable frame (not shown) which supports the instrument.

A bankvof lamps 16,- controlled by a switch e circuit of the indicator.

,of my invention has been set forth above and need not berepeatedfi 7 "have described theprincip e of operation of In accordance with the atent' statutes" I my invention, together with thJapparatu's which I; now consider to represent t e best embodiment thereof; but I desire to have; it

I be sync ,unde'rstoodthat the apparatus shown is only illustrative and that the invention can be carried out by other means} i What I claimas new; anddesire to secure I by Letters Patent of the United States, is% 2 1. A synchronism-indicator*comprising' a constantecurrent transformer responsive to exchanglerrcurrents' between the machines to onizedj,;a i1d:a SignaLoReratiVeIyrelatedltosaid transformer.

2. A synchronism-indicatori comprising a constant'current transformerhaving its primary coii responsivetoexchange-currents between the machines to" be synchronized, and its secondary coil in circuit ,with a signallamp.

'3. A synchroni'sm indicator comprising two relatively movable coils, one responsiveto exchan e-currcnts between the machines to be synchronized, and-the other connected with an indicating device.

4. Asyhchronism-in two relativelymovable coils, one responsive to exchange -currents between the machines -nected with a signal-lamp, and a sprin dicator comprising opposing the-relative movement of said coils;

5. A synchronism indicator comprising a transformer havinga'; ionaryco1l'resp0nsive to exchange-current between the ma chines to be synchronized, nd a pivoted coil connected with the'signal-lamp.

6. A synchronism-mdicator comprising a transformer having a stationary coil responsive to exchange-currents between the machines to be synchronized, a pivoted coil conposinithe movement of said pivoted coil.

to be synchronized an'd'the other connected I witha signal-lamp, andmeans for yieldingly.

synchronism-indicator comprising a transformer having a stationary c011 responsive to exchange-currents between the machines to. be synchronized and a pivoted coil connected with a signal-lamp, a spring oppos-' ing the'movement of said plvoted coil, and an eccentric. movingv with the pivoted coil :and to which said spring is connected.

8. In a synchronlsm-indicator, the combi nation with two or more alternating-current machlnes, of a s1gnal-la1np,and means for supplying it with constant current during the greater portion of phase displacement of said machines and reducing said current when the machinesc'ome nearly instep;

v 9.; In a synchronisrn-indicator, the combination with two alternatin-current machines, oftwo relatively mova le coils which repel each otherwhen the phase displacement of said machines is great, and'a signal-lamp which fluctuatesin brilliancywhen the phase 1 

